Such a clamp is disclosed in U.S. Pat. No. 4,241,477. The clamp shown therein is made from a relatively rigid thick material and the lip is from a resilient relatively thin material. In the description it is indicated that those parts might be integrally formed. Engagement of the lip to the related part of the leg is realized only by resilient deformation of this lip which snaps behind a protruding part of the related leg. This engagement can be realized by engaging a tab of the resilient lip. However, such engagement may result in damage of the nails or finger of the user engaging the tab protruding from the paper clip in the position of use and a relatively considerable force will be required to disengage the resilient lip.